1. Technical Field
This invention relates to computer and facsimile transmissions, specifically a method to efficiently and reliably guarantee transmission and receipt of faxes documents from non-internet devices routed through internet connectivity based upon extrinsic circumstances: asynchronously, synchronously, pre-call phone number validation.
2. Terms
The terms “facsimile” and “fax” shall be used interchangeably and refer to data that is transmitted on the protocol generically known as “T.30”.
The term “telephonic” and “telephony” shall generally be considered to be the transmission of audio signals on a PSTN (“Packet Switched Telephony Network”) according to generally accepted protocols.
The term “ATA” shall mean analog telephone adapter, which shall generally mean a device that interfaces a traditional telephone handset with a TCP/IP interface.
The term “T.30” shall generally mean a protocol for the transmission of facsimile documents that conform to the “Group-2” or “Group-3” protocol.
The term “HTTP” shall generally mean Hypertext Transfer Protocol (HTTP) which is an application layer protocol for distributed, collaborative, hypermedia information systems.
The term “SIP” shall mean the Session Initiation Protocol which is a signaling protocol, widely used for controlling multimedia communication sessions such as voice and video calls over Internet Protocol (IP). The protocol can be used for creating, modifying and terminating two-party (unicast) or multiparty (multicast) sessions consisting of one or several media streams.
The term “ITU G.729” is an ITU (International Telecommunications Union, www.itu.int) standard codec. It offers toll quality speech at a reasonably low bit rate of 8 Kbps.
The term “PSTN” shall mean a public switched telephone network (PSTN) is the network of the world's public circuit-switched telephone networks.
3. Introduction
For more than a decade now facsimile (aka fax and/or faxing) has been an important staple in business communications. It has provided secure, reliable real-time and legally significant document transfer. Features which many more modern platforms have attempted to replace but for which have yet to achieve any significant market share. While the technology has been evolving, the original T.30 protocol has mostly seen minor modifications to accommodate faster data transfer encodings (i.e. V.17 with speeds at 14400, 12000 9600, 7200 bps.)
Now referring to FIG. 1 illustrating the prior art method 100 of a typical fax transmission. A call is started 110 by dialing a phone number 115. If the fax tone is detected 125, 130 then a fax transfer is initiated 150 by transferring sequential data blocks 155 via T.30 160 until the fax is complete 165.
Now referring to FIG. 2 depicting the prior art system 200 of a first fax machine 210 connected to a second fax machine 220 via a PSTN 230. The connections from the fax machines 210,220 is well known in the arts and can be done via regular telephone line wire, a channel bank, and/or other similar technologies.
Although the use of facsimile transmissions is well known in the prior arts and familiar to most individuals, the architecture of a typical PSTN and method of sending faxes are depicted on FIG. 1 (method of transmitting a fax) and FIG. 2 (architecture of the fax communication through a PSTN) to provide a background.
As the fax machine became more and more popular a need for volume processing, automation and elimination of consumables became in high demand, leading to the creation of “fax servers”. The prior art architecture 300 of a typical network utilizing a fax server 360 is shown on FIG. 3. The general operation of a typical fax server 360 consists of using a computer workstation 310 to send fax documents 315 to the fax server 360 via proprietary protocols using an email_server 320 and/or webserver 330, the fax server 360 then converts the fax documents 315 to fax images 365, the fax server 360 then streams the fax image to the PSTN to the dedicated fax hardware 210 and which is connected to a phone line 205 T.30 lines, to determine if the transmission was successful, the fax server 360 then queues the fax result, the workstation then queries the fax server 360 for result. The implementation of the first generation of fax server 360 was based on dedicated computer based telephony cards which solely performed the task of sending and receiving fax via the standard telephone network (PSTN 230). As the internet became popular, the desire for users to have faxes sent and received from email came into high demand. This requirement necessitated that fax servers directly communicate with email servers. Electronic fax services were developed provided this functionality without the user having to own fax machines or fax servers. To standardize the method in which companies could integrate fax with email, the T.37 specification was created and very widely adopted. Because users did not commonly have tools for converting documents to TIFF Class F document format as required by T.37, fax servers additionally had to provide programs or services to perform this conversion automatically for users (e.g. to convert a TIFF Class F document to the Adobe PDF format).
The use of the email to fax system consists of the following steps as further shown on FIG. 4. The workstation 310 sends a fax document to the email server 320 via the T.37 protocol, the email server 320 sends fax documents to the fax server 360 via various networking protocols, the fax server 360 then converts documents to fax image, the fax server 360 then streams the fax transmission to the PSTN via dedicated fax hardware using the T.30 protocol 455 460. When the fax document transmission is complete the fax server 360 then emails a notification which is then retrieved by the workstation.
As local private networks continued a fast paced adoption of internet technology throughout all market segments the demand for doing telephony over IP became a dominant theme. This lead to the creation of a “media gateway” for the purpose of transporting voice, fax and data over IP. This introduced a large number of new protocols, standards and problems. The industry first attempted to use audio protocols such as G.711/RTP to carry fax data, but then adopted T.38 as the preferred protocol for faxing over IP.
As noted, the term “ATA” shall mean an analog telephone adapter, which shall generally mean a device that interfaces a traditional telephone handset and/or traditional fax interface with a TCP/IP interface. “ATA's” referred to as VoIP Gateways, TA (Terminal Adapter), FXS Adapter, etc. Most common ATAs use either the SIP (session initiation protocol) or IAX industry standard protocol. An exemplary architecture that demonstrates the connection of a traditional fax machine that is normally connected to a PSTN, but connected to an ATA is shown on FIG. 5. Now referring to FIG. 5 where the ATA 520 is connected to the fax machine 510. The ATA 520 is further connected to the Internet 340.
While T.38 was created with packet networks in mind, it was not designed for use over the open internet. The following issues were left unresolved:                i) T.38 has no inherent facility to provide encryption or secure transport over the internet. This means that those market segments which are regulated by HIPPA and SOX compliance regulations are prohibited by law from using it.        ii) While T.38 was designed to significantly improve the ability for fax transmission to work with a certain degree of packet loss and latency, the internet has proven to often provide and even lower quality of network than T.38 can survive.        iii) Because T.38 was designed with local and private networks in mind, the concept of cost per packet was not considered. This translates into T.38 being significantly more expensive than other audio transport protocols.        iv) An unexpected problem with T.38 was that the Media Gateway companies implementing it were not focused on Fax solutions and thus did not invest as heavily into implementing T.38 which led to a large number of incompatibilities between vendors. Most still struggle today to have truly reliable fax even when communicating between their own devices.        
Now referring to FIG. 7. The method of using the traditional fax machine with an ATA is typically as follows. The fax machine transmits fax images to the ATA via T.30. The ATA then transmits fax image(s) over network (and/or internet) to a media gateway using the SIP, MGCP, H.323, G.729, G.711, and/or T.38 protocols. The Media Gateway then transmits any image via PSTN using T.30 to the destination fax machine.
While this architecture for transmitting facsimile documents using ATA's is possible, it has some inherent limitations as a consequence of the use of the T.38 protocol. For example, T.38 has no inherent facility to provide encryption or secure transport over the internet. As a result, users that desire HIPPA and/or SOX compliance regulations may be prohibited from using it. Also, despite that T.38 was designed to significantly improve the ability for fax transmission to work with a certain degree of packet loss and latency, the internet as a transmission network often has even lower quality of network services that can make T.38 viable. Furthermore, since T.38 was designed with local and private networks in mind, the concept of cost per packet was not considered. As a result, the use of T.38 on metered networks is significantly more expensive than other audio transport protocols. Finally, an unanticipated problem with T.38 is that the Media Gateway companies implementing it as a protocol, has resulted in a large number of incompatibilities between vendors and/or service providers.
When fax machines migrated to using VoIP media gateways, fax servers likewise made the same migration, as shown in FIG. 6. Unfortunately this simply exacerbated the aforementioned problem due to the larger volumes of facsimile data sent by the fax server as compared to a single fax machine.
The typical operation of a fax server with a media gateway is as follows and as shown in FIG. 5. The Workstation sends a fax document to fax server via proprietary protocols. The Fax Server converts the document to fax image. The Fax Server then streams fax image to media gateway via the SIP, MGCP, H.323, G.729, G.711, and/or T.38 protocols. The Media Gateway the streams fax image to PSTN via the T.30 protocol. After the facsimile has transmitted, the queries and queues the result from the Fax Server. The workstation then queries the fax server for a transmission result.
Now referring to FIG. 6, the operation of the Media Gateway with an email connection is illustrated. The workstation sends fax document to email server via T.37. The Email Server sends fax document to fax server via various techniques. The Fax Server then converts document to fax image. The Fax Server streams fax image to media gateway via SIP, MGCP, H.323, G.729, G.711, and T.38. The Media Gateway then streams fax to PSTN via T.30. The Fax Server emails a notification of fax transmission. The Workstation then retrieves email notification.
One attempted solution to the problem of using T.38 over the internet was to create an ATA which utilized a store and forward model of communication. This architecture is similar to the email to fax model computer based users were becoming comfortable with. This design created a number of new limitations which has prevented wide adoption of the technology.
The store and forward architecture adds a significant additional cost to the manufacturing cost of the ATA device. The design requires that the device be able to completely buffer the entire contents of the largest fax it would support sending. While not as frequently performed as sending 1 or 2 page faxes, it is well known that many users indeed send 100 to 500 page faxes on occasion.
Also a single page with a high graphical content can exceed a megabyte in size. As such a series of graphically intensive faxes can significantly increase the storage requirements of the ATA. This extra memory requirement increases the product cost which may limit potential purchasers.
The operation of the first attempted solution is shown on FIG. 9. In the first step the fax machine then transmits the fax image to ATA via T.30. Then the fax machine/server transmits the fax image to the fax gateway (FG). The Fax Server then Streams the fax image to Media Gateway via SIP, MGCP, H.323, G.729, G.711, and T.38. The Media Gateway then transmits the fax image to PSTN via T.30. The fax server then queues the results from the Fax Gateway. The Fax Gateway prints then prints a notification to Fax Machine.
It is a requirement by the FCC that any device which provides a handset and a standardized telephony dial tone must support the ability to dial 911 for emergency calls. As a consequence, the majority of the fax machines must support a dial tone interface. For a fax device that is connected to an ATA to successfully operate without modification, the ATA has to simulate a dial-tone and full standard telephony operation. However these devices were specifically designed for fax, and thus did not support real-time audio operation.
End Users and operators have discovered that fax machines connected to ATA's additionally did not operate as expected. In the operation of a standard fax machine a user takes the phone off hook, and listens in real-time to the audio for the dial and answer of a remote device. This allows them to instantly hear if they mis-dialed the number. In a store and forward model there is no live audio associated with the call, only a simulated audio session. This means that an entire 100 page fax will be scanned and sent to a remote server before any indication of failure will be presented to the user. Typically requiring them to rescan and send the fax.
Therefore, the configuration of these media networking communication systems requires much information and configuration to obtain optimal operation and functionality by each of the individual components and on the larger system as a whole entity. This continues to be an urgent issue due to the speed and number of changes that are increasingly developed, disseminated, and implemented by all of the various vendors involved with these complex media networking systems. The integration, stability and reliability is routine in question due to the vast number of networking components involved and the amount of effort and time really necessary to prove full interoperability is successful without any degradation of the networking systems.
The “scan and send” of large amounts of data through fax devices remains a vital part of day to day operations for many businesses. The merging of this faxing data stream on to the IP network is happening through various avenues, but each mechanism has left unresolved issues for the fax users to deal with.